Hi, in Section 3.2 there is now specification for sending a 1280 byte probe packet to test the path between the ingress and egress. The stated goal is to ensure that a 1280 byte packet can traverse the tunnel without fragmentation.
However, if there are other tunnels on the path from the first tunnel ingress toward the corresponding egress, it is possible that another tunnel could be fragmenting and reassembling the probe packet before it arrives at the final egress. And, fragmentation and reassembly closer to the middle of the network is much worse than fragmentation and reassembly nearer the edges of the network. This is why I have proposed a new "Don't Fragment" bit in the GRE header. It can be set by the first tunnel ingress to tell other tunnels not to fragment the packet that is being used as a probe. Fragmentation and reassembly of probe packets must be avoided if we are to avoid fragmentation and reassembly of data packets. Also, it might be worth noting that this is not the first time a tunnel loopback test packet has been specified. A similar facility is specified in Section 8 of RFC5969. Thanks - Fred [email protected] > -----Original Message----- > From: I-D-Announce [mailto:[email protected]] On Behalf Of > [email protected] > Sent: Monday, April 13, 2015 4:14 AM > To: [email protected] > Cc: [email protected] > Subject: I-D Action: draft-ietf-intarea-gre-ipv6-07.txt > > > A New Internet-Draft is available from the on-line Internet-Drafts > directories. > This draft is a work item of the Internet Area Working Group Working Group > of the IETF. > > Title : IPv6 Support for Generic Routing Encapsulation (GRE) > Authors : Carlos Pignataro > Ron Bonica > Suresh Krishnan > Filename : draft-ietf-intarea-gre-ipv6-07.txt > Pages : 8 > Date : 2015-04-13 > > Abstract: > Generic Routing Encapsulation (GRE) can be used to carry any network- > layer payload protocol over any network-layer delivery protocol. GRE > procedures are specified for IPv4, used as either the payload or > delivery protocol. However, GRE procedures are not specified for > IPv6. > > This document specifies GRE procedures for IPv6, used as either the > payload or delivery protocol. It updates the GRE specification, RFC > 2784. > > > > The IETF datatracker status page for this draft is: > https://datatracker.ietf.org/doc/draft-ietf-intarea-gre-ipv6/ > > There's also a htmlized version available at: > http://tools.ietf.org/html/draft-ietf-intarea-gre-ipv6-07 > > A diff from the previous version is available at: > http://www.ietf.org/rfcdiff?url2=draft-ietf-intarea-gre-ipv6-07 > > > Please note that it may take a couple of minutes from the time of submission > until the htmlized version and diff are available at tools.ietf.org. > > Internet-Drafts are also available by anonymous FTP at: > ftp://ftp.ietf.org/internet-drafts/ > > _______________________________________________ > I-D-Announce mailing list > [email protected] > https://www.ietf.org/mailman/listinfo/i-d-announce > Internet-Draft directories: http://www.ietf.org/shadow.html > or ftp://ftp.ietf.org/ietf/1shadow-sites.txt _______________________________________________ Int-area mailing list [email protected] https://www.ietf.org/mailman/listinfo/int-area
